Please Note: This article is written for users of the following Microsoft Excel versions: 2007, 2010, 2013, 2016, 2019, and Excel in Microsoft 365. If you are using an earlier version (Excel 2003 or earlier), this tip may not work for you. For a version of this tip written specifically for earlier versions of Excel, click here: How Excel Stores Dates and Times.

How Excel Stores Dates and Times

Written by Allen Wyatt (last updated March 13, 2021)
This tip applies to Excel 2007, 2010, 2013, 2016, 2019, and Excel in Microsoft 365


Internally, Excel stores a date or time as a number. The whole part of the number (the part to the left of the decimal point) represents the number of days starting with an arbitrary starting point (typically January 1, 1900). The decimal portion (the part to the right of the decimal point) represents the time for that date. These internal representations of dates and times are often referred to as serial numbers.

To see how this works, enter the number 23 in a cell. If you have not previously formatted the cell, Excel uses the General format, displaying the number simply as 23. If you later format this cell using a date format—m/d/yy, for instance—Excel changes the display to 1/23/00, or January 23, 1900. (January 1, 1900, is 1; January 2 is 2; January 3 is 3; and so on.)

The portion to the right of the decimal point represents a fractional portion of a day. Thus, a single second would be equal to approximately 0.00001157407, since that is equal to 1 (a day) divided by 86,400 (the number of seconds in a day).

Since Excel stores dates and times as serial numbers, you can do math on them. For instance, if you wanted to determine the number of days between two dates, or the amount of time between two times, simply subtract them from each other. The result is the number of days and fractions of days between the two.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (11337) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, and Excel in Microsoft 365. You can find a version of this tip for the older menu interface of Excel here: How Excel Stores Dates and Times.

Author Bio

Allen Wyatt

With more than 50 non-fiction books and numerous magazine articles to his credit, Allen Wyatt is an internationally recognized author. He is president of Sharon Parq Associates, a computer and publishing services company. ...

MORE FROM ALLEN

Fast AutoFill

Want to fill a long column with predictive data? It's easy to do by using AutoFill and a double-click of the mouse.

Discover More

Simplifying the Font List

Excel normally displays the font list on the toolbar or using the very fonts it is displaying. Here's how to change that ...

Discover More

Changing the Axis and Gridline Default Color

When you want to change the defaults used for charts, a chart template is the way to go. This tip shows how easy it is to ...

Discover More

Save Time and Supercharge Excel! Automate virtually any routine task and save yourself hours, days, maybe even weeks. Then, learn how to make Excel do things you thought were simply impossible! Mastering advanced Excel macros has never been easier. Check out Excel 2010 VBA and Macros today!

More ExcelTips (ribbon)

Weird Mouse Shortcut

If you like to use the mouse in your worksheet navigation efforts, you'll want to pay attention to this tip. Here you ...

Discover More

Shortcut to Move between Two Worksheets

Moving between to adjacent worksheets is easy; Excel provides a shortcut key to do the trick. If you want to move between ...

Discover More

Appearance of Excel on the Taskbar

Do you want Excel to use a task button, on the Windows Taskbar, for each of your open worksheets? Then just make this ...

Discover More
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

View most recent newsletter.

Comments

If you would like to add an image to your comment (not an avatar, but an image to help in making the point of your comment), include the characters [{fig}] (all 7 characters, in the sequence shown) in your comment text. You’ll be prompted to upload your image when you submit the comment. Maximum image size is 6Mpixels. Images larger than 600px wide or 1000px tall will be reduced. Up to three images may be included in a comment. All images are subject to review. Commenting privileges may be curtailed if inappropriate images are posted.

What is nine minus 1?

There are currently no comments for this tip. (Be the first to leave your comment—just use the simple form above!)


This Site

Got a version of Excel that uses the ribbon interface (Excel 2007 or later)? This site is for you! If you use an earlier version of Excel, visit our ExcelTips site focusing on the menu interface.

Newest Tips
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

(Your e-mail address is not shared with anyone, ever.)

View the most recent newsletter.